Shank instruments which at the distal end of a shank comprise an instrument head with a tool arranged on this head are applied in the field of medicine and there in particular in the field of endoscopy. Instruments of this type, with which it can be the case of gripping or cutting instruments, are moreover applied in other fields, for example with technoscopes for the application in cavities of technical objects.
The starting point of the invention is formed by those instruments, with which the instrument head can be angled (bent) relative to the shank, and the tool or at least a part of the tool can be angled relative to a tool carrier of the instrument head. Such an instrument is known from US 2007/0208375 A1. This instrument comprises an instrument head which is arranged distally of a shank and which comprises a tool carrier articulated on the distal end of the shank via an elongate joint part. The tool carrier is articulated on the distal end of the joint part in an angularly bendable manner, in the bending angle plane of the joint part. The tool carrier is coupled to the shank via a roller body pairing for the purpose of ensuring a controlled angulation of the tool carrier relative to the shank and to the joint part. Pull cables which act upon the joint part in a direct manner serve for the control of the angulation of the instrument head.
Hereby, it has found to be disadvantageous that, inherently of the design, only comparatively small moments can be transmitted onto the joint part, for the control of the angulation of the instrument head. A further disadvantage of this instrument lies in the fact that the joint part itself only undergoes a lateral deflection of +/−60° even with a total angular bending of the instrument head of +/−120°, so that the angular bending of the instrument head relative to the shank can only be set in a comparatively coarse manner.